The screw-in inserts that the seat-plugs slot into are surely removable for a reason

These things are sort of intricate. I can't think of anything with fine detail molded into the hulls, only places for such stuff to be screwed in. That's just my guess.

mingle wrote:

So how will you go if/when you need to remove them from your boats and you've glued them in?.

I thought of this while installing. I decided that if they wouldn't pull out, I could drill them out. There is a little gap between the bottom of the insert and the bottom of the hole that hopefully would prevent damage to the bottom of the hole.

The screw inserts arrived last week but I haven't had a chance to fit them yet. I did check out the tapping option but realised that a tap is too long to cut the thread. You would have to grind the tapered end off.The thread is very close to a 20mm bolt. I was going to grind some vertical slots into the M20 bolt to make a tap. Better to ruin a $3 bolt rather than a $35 tap. Talking to my Hobie dealer they have been fitting them (using a heat gun) to older boats by CAREFULLY heating the peg hole until it 'sweats' and then screwing the inserts directly into the softened plastic. They use the twist lock pegs to hold and turn the insert.I'm a bit wary of overheating the plastic. I thought I'd try some boiling water first.

I got around to tapping the seat peg holes. Cost about $10. $3 for the M20 bolt and $7 for the 30mm socket to drive it! I ground 4 slots into the bolt to turn it into a tap of sorts

Turning 1/8 to 1/4 turn forward, then back I carefully cut the thread, removing the bolt after every full turn or so to clean out the thread.

It only took a couple of minutes to cut the thread in each hole

The plugs screwed in easily and felt tight.

Just to be sure I added some Sikaflex marine sealant to threads. Messy, but it should prevent any backing out of the plug. The M20 thread works but is not the exact thread -which I'm guessing is an imperial size? I couldn't source the exact thread easily here.

An assembled bayonet fitting makes a good screw in tool

PS-It was tight but I did manage to fit the bayonets through the two layers of seat padding -standard and iComfort that we use.The bayonet fitting is a huge improvement over the expanding plug type seat post which I could never get tight enough on the TI.

Brilliant!I just wanted to acknowledge you for your perseverance and ingenuity in designing this "tap"; you are very clever . (Just be carefull, I can hear thinking..."Hummm, now what else can I tap and thread on my boat?") .

Also for the contributions of the other members regarding various glues and epoxies. I'll keep a copy of this article in my "how to fix" folder. Good work everyone!

If I were still using my old seats I would definitely go this route to install the new "twist and lock pegs".

Thanks for those comments sun E. Much appreciated! I won't be tapping anything else that big! I thought of using the bolt after seeing how easily a thread can be cut into poly. I used to tap any holes I drilled for fitting accessories but then I got lazy and just drilled holes 2 drill sizes smaller and used the accessories bolt, driven by a cordless screwdriver, to do the cutting. Left a perfect thread each time.In this case of course Hobie had provided the right sized hole, so the job was made easy- once I got the 30mm socket!